If a backup set is expired， what can you do to correct the problem？（）  

• A、 Change the retention criteria.
• B、 Make the lost backup set pieces available to RMAN again.
• C、 Run the crosscheck command to correct the location for the backup set piece contained in the metadata.
• D、 Nothing. The backup set piece is lost forever.
• E、 Call Oracle support，their assistance is required.